1. Field of the Invention
This invention relates to infrared thermopile systems for semiconductor process monitoring and control, and to a method of monitoring and controlling semiconductor processes using infrared thermopile sensing of conditions in and/or affecting such processes.
2. Description of the Related Art
Sensors and monitoring devices used in the semiconductor industry generally have two purposes. One type of such device is used as a safety sensor to warn persons (e.g., personnel operating the semiconductor process equipment or otherwise in proximity to such equipment) of the presence of toxic or otherwise hazardous materials associated with the process in the ambient environment of the process system. These safety sensors, sometimes termed xe2x80x9clife safety sensors,xe2x80x9d have lower detection limits consistent with the threshold limit values (TLVs) of the gases and vapors to be detected. By way of example, an arsine gas safety sensor may have a lower detection limit of 50 parts per billion by volume (ppbv), so that any concentration of arsine that is 50 ppbv or higher will be sensed by the safety sensor device.
The other purpose for which sensors and monitoring devices have been used in the semiconductor industry is controlling semiconductor process. Examples include SiF4 ultraviolet (UV) emission detectors that are used to provide a signal indicative of the completion of chamber cleaning operations.
The semiconductor manufacturing field continues to seek improvements in process monitoring and control.
The present invention relates to infrared thermopile systems for semiconductor process monitoring and control, and to a method of monitoring and controlling semiconductor processes using infrared thermopile sensing of conditions in and/or affecting such processes.
In one aspect, the present invention relates to a semiconductor process system including flow circuitry for flow of a process gas. The system comprises:
a gas sampling region for the process gas;
an infrared radiation source constructed and arranged to transmit infrared radiation through the gas sampling region;
a thermopile detector constructed and arranged to receive infrared radiation after the transmission thereof through the gas sampling region and to responsively generate an output signal correlative of concentration of at least one selected component of the process gas; and
process control means arranged to receive the output of the thermopile detector and to responsively control one or more process conditions in and/or affecting the semiconductor process system.
In another aspect, the invention relates to a method of operating a semiconductor process including processing of or with a gas, said method comprising sensing concentration of a desired component of said gas with a thermopile detector, generating an output from said thermopile detector indicative of concentration of said selected component of said gas, and controlling one or more conditions in and/or affecting the semiconductor process, in response to said output.
Other aspects, features and embodiments of the invention will be more fully apparent from the ensuing disclosure and appended claims.